Everything you ever wanted to know about how electric bikes get their power

Batteries are at the heart of many aspects of modern lives. They power our phones, from 2030 they'll power our cars - and quite often they power our bikes too. Every battery does the same basic thing, but the difference between them is huge.

In the same way that LEDs quickly became the only option for bike lights, lithium-ion is now completely dominant when it comes to e-bike batteries.

It's the same technology you’ll find everywhere from your phone to an electric drill to a Tesla supercar. Lithium-ion batteries are smaller and lighter than the lead acid batteries they replace, meaning lighter bikes and more range for less weight, while the reduced environmental and safety risks make them far more suited to consumer use.

Lithium-ion batteries last much longer than lead acid batteries. A lead acid battery typically needs to be replaced after 200-300 charges, whilst a lithium-ion battery is likely to last between 500-2000 charges, depending on battery quality. Charging is also a lot more efficient, with a fast charger able to fill up an e-bike battery in just a few hours. 

Capacity (Ah and Wh)

Capacity is usually measured in amp hours (Ah) or watt hours (Wh). They're both essentially measuring the same thing but the watt hour is taking over as the standard because it's a bit more consumer-friendly.

The relationship is simple to explain: a battery with a 10Ah capacity is theoretically capable of supplying 1 ampere of current for 10 hours (or 10 amperes for 1 hour). Multiply that by the voltage the battery supplies (in e-bikes this is usually 36v, although 24v and 48v systems are also available) and you get the capacity in watt hours. Power – measured in watts – is simply the voltage multiplied by the current. So a 10Ah, 36V battery is 360Wh.

E-bike batteries have a range of capacities. The battery is usually the most expensive part of the bike to produce, so cheaper bikes tend to have smaller batteries. The cheapest bikes have batteries of around 150-200Wh, with 300-500Wh the standard range.

COSWHEEL-T20 E-bike equipped with 18650 li-ion battery, 48V 15/20Ah capacity, easy removable, fast and convenient to charge, and has super long range ability.

Lithium-ion, on the other hand, has less environmental impact as a technology, and fewer regulations, meaning that the batteries can be both disposed of and recycled more easily.